HTTP Header Content-Length question?

Question

Im capturing traces using WireShark and I have a question about the basic syntax for the items in the header (Content-Length, Accept, Host, etc).

The syntax I see is:
Content-Length: 10/n/r for example

Are the fields case sensitive (must be as above) or can it be:
content-length: 10

Also is the space between the : and the length (10) required or can it be:
Content-Length:10

I need to parse these fields and I need to know this.

djbckr · Accepted Answer

The general rule is that:
 - a sender should send well-formed data
 - a receiver should accept and parse imperfect data within reason

The headers *should* be in the proper case, then a colon (:) then a space, then the header value. Most sites honor this, but you can't necessarily absolutely rely on it.

So, short answer: accept everything within sensible boundaries.

Examples from W3C: http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html
Examples from Wikipedia: http://en.wikipedia.org/wiki/List_of_HTTP_header_fields

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HTTP Header Content-Length question?

1 Answer